NAPAC2022 - List of Authors (Johnson, R.P.)

Paper	Title	Page
TUPA09	Designing Accelerator-Driven Experiments for Accelerator-Driven Reactors	360
	M.A. Cummings, R.J. Abrams, R.P. Johnson, J.D. Lobo, T.J. Roberts Muons, Inc, Illinois, USA
	Muons, Inc., with its collaborators, to the best of our knowledge is the only one of the several reactor concept companies in the US that is concentrating on an accelerator-driven subcritical high-power reactor design. The major objection to such systems has been that short interruptions of beam of even a few seconds would turn off fission power long enough to induce temperature-gradient shocks and subsequent fatigue of solid fuel elements. MuSTAR solves this problem by using a molten-salt fuel. MuSTAR is a reactor design that not only includes a particle accelerator as an integral part, but has several innovative features that make it a compelling solution to many problems. We note that the ADSR concepts being pursued by the Chinese Academy of Science (ADANES) and the Belgians (MYRRHA) are based on traditional solid fuel elements and require exceptional stability from their accelerator.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA09
About •	Received ※ 03 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 29 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPA11	Magnet System for a Compact Microtron Source	363
	S.A. Kahn, R.J. Abrams, M.A. Cummings, R.P. Johnson, G.M. Kazakevich Muons, Inc, Illinois, USA
	Funding: Work supported in part by U.S. D.O.E. SBIR grant DE-SC0013795. A microtron can be an effective intense electron source. It can use less RF power than a linac to produce a similar energy because the beam will pass through the RF cavity several times. To produce a high-quality low-emittance beam with a microtron requires a magnetic system with a field uniformity $δ B/B<0.001. Field quality for a compact microtron with fewer turns is more difficult to achieve. In this study we describe the magnet for a compact S-band microtron that will achieve the necessary field requirements. The shaping of the magnet poles and shimming of the magnet iron at the outer extent of the poles will be employed to provide field uniformity. The extraction of the beam will be discussed.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA11
About •	Received ※ 04 August 2022 — Revised ※ 14 August 2022 — Accepted ※ 06 September 2022 — Issue date ※ 08 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPA13	Affordable, Efficient Injection-Locked Magnetrons for Superconducting Cavities	366
	M. Popovic, M.A. Cummings, R.P. Johnson, S.A. Kahn, R.R. Lentz, M.L. Neubauer, T. Wynn Muons, Inc, Illinois, USA T. Blassick, J.K. Wessel Richardson Electronics Ltd, Lafox, Illinois, USA
	Funding: DE-SC0022586. Existing magnetrons that are typically used to study methods of control or lifetime improvements for SRF accelerators are built for much different applications such kitchen microwave ovens (1kW, 2.45 GHz) or industrial heating (100 kW, 915 MHz). In this project, Muons, Inc. will work with an industrial partner to develop fast and flexible manufacturing techniques to allow many ideas to be tested for construction variations that enable new phase and amplitude injection locking control methods, longer lifetime, and inexpensive refurbishing resulting in the lowest possible life-cycle costs. In Phase II magnetron sources will be tested on SRF cavities to accelerate an electron beam at JLab. A magnetron operating at 650 MHz will be constructed and tested with our novel patented subcritical voltage operation methods to drive an SRF cavity. The choice of 650 MHz is an optimal frequency for magnetron efficiency. The critical areas of magnetron manufacturing and design affecting life-cycle costs that will be modeled for improvement include: Q_ext, filaments, magnetic field, vane design, and novel control of outgassing.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA13
About •	Received ※ 05 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 23 August 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEYD6	Design of a PIP-II Era Mu2e Experiment	568
	M.A. Cummings, R.J. Abrams, R.P. Johnson, T.J. Roberts Muons, Inc, Illinois, USA D.V. Neuffer Fermilab, Batavia, Illinois, USA
	We propose a design of an upgraded Mu2e experiment for the future Fermilab PIP-II era based on the muon collider front end. The consensus is that such an upgrade should provide a factor of 10 increase in the rate of stopping muons in the experimental target. The current Mu2e design is optimized for 8 kW of protons at 8 GeV. The PIP-II upgrade project is a 250-meter-long CW linac capable of accelerating a 2-mA proton beam to a kinetic energy of 800 MeV (total power 1.6 MW). This would significantly improve the Fermilab proton source to enable next-generation intensity frontier experiments. But using this 800 MeV beam poses challenges to the Mu2E experiment. Bright muon beams generated from sources designed for muon collider and neutrino factory facilities have been shown to generate two orders of magnitude more muons per proton than the current Mu2e production target and solenoid. In contrast to the current Mu2e, the muon collider design has forward-production of muons from the target.
	Slides WEYD6 [1.937 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEYD6
About •	Received ※ 06 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 09 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Designing Accelerator-Driven Experiments for Accelerator-Driven Reactors

360

M.A. Cummings, R.J. Abrams, R.P. Johnson, J.D. Lobo, T.J. Roberts
Muons, Inc, Illinois, USA

Muons, Inc., with its collaborators, to the best of our knowledge is the only one of the several reactor concept companies in the US that is concentrating on an accelerator-driven subcritical high-power reactor design. The major objection to such systems has been that short interruptions of beam of even a few seconds would turn off fission power long enough to induce temperature-gradient shocks and subsequent fatigue of solid fuel elements. Mu*STAR solves this problem by using a molten-salt fuel. Mu*STAR is a reactor design that not only includes a particle accelerator as an integral part, but has several innovative features that make it a compelling solution to many problems. We note that the ADSR concepts being pursued by the Chinese Academy of Science (ADANES) and the Belgians (MYRRHA) are based on traditional solid fuel elements and require exceptional stability from their accelerator.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA09

About •

Received ※ 03 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 29 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPA11

Magnet System for a Compact Microtron Source

363

S.A. Kahn, R.J. Abrams, M.A. Cummings, R.P. Johnson, G.M. Kazakevich
Muons, Inc, Illinois, USA

Funding: Work supported in part by U.S. D.O.E. SBIR grant DE-SC0013795.
A microtron can be an effective intense electron source. It can use less RF power than a linac to produce a similar energy because the beam will pass through the RF cavity several times. To produce a high-quality low-emittance beam with a microtron requires a magnetic system with a field uniformity $δ B/B<0.001. Field quality for a compact microtron with fewer turns is more difficult to achieve. In this study we describe the magnet for a compact S-band microtron that will achieve the necessary field requirements. The shaping of the magnet poles and shimming of the magnet iron at the outer extent of the poles will be employed to provide field uniformity. The extraction of the beam will be discussed.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA11

About •

Received ※ 04 August 2022 — Revised ※ 14 August 2022 — Accepted ※ 06 September 2022 — Issue date ※ 08 October 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPA13

Affordable, Efficient Injection-Locked Magnetrons for Superconducting Cavities

366

M. Popovic, M.A. Cummings, R.P. Johnson, S.A. Kahn, R.R. Lentz, M.L. Neubauer, T. Wynn
Muons, Inc, Illinois, USA
T. Blassick, J.K. Wessel
Richardson Electronics Ltd, Lafox, Illinois, USA

Funding: DE-SC0022586.
Existing magnetrons that are typically used to study methods of control or lifetime improvements for SRF accelerators are built for much different applications such kitchen microwave ovens (1kW, 2.45 GHz) or industrial heating (100 kW, 915 MHz). In this project, Muons, Inc. will work with an industrial partner to develop fast and flexible manufacturing techniques to allow many ideas to be tested for construction variations that enable new phase and amplitude injection locking control methods, longer lifetime, and inexpensive refurbishing resulting in the lowest possible life-cycle costs. In Phase II magnetron sources will be tested on SRF cavities to accelerate an electron beam at JLab. A magnetron operating at 650 MHz will be constructed and tested with our novel patented subcritical voltage operation methods to drive an SRF cavity. The choice of 650 MHz is an optimal frequency for magnetron efficiency. The critical areas of magnetron manufacturing and design affecting life-cycle costs that will be modeled for improvement include: Q_ext, filaments, magnetic field, vane design, and novel control of outgassing.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA13

About •

Received ※ 05 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 23 August 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEYD6

Design of a PIP-II Era Mu2e Experiment

568

M.A. Cummings, R.J. Abrams, R.P. Johnson, T.J. Roberts
Muons, Inc, Illinois, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA

We propose a design of an upgraded Mu2e experiment for the future Fermilab PIP-II era based on the muon collider front end. The consensus is that such an upgrade should provide a factor of 10 increase in the rate of stopping muons in the experimental target. The current Mu2e design is optimized for 8 kW of protons at 8 GeV. The PIP-II upgrade project is a 250-meter-long CW linac capable of accelerating a 2-mA proton beam to a kinetic energy of 800 MeV (total power 1.6 MW). This would significantly improve the Fermilab proton source to enable next-generation intensity frontier experiments. But using this 800 MeV beam poses challenges to the Mu2E experiment. Bright muon beams generated from sources designed for muon collider and neutrino factory facilities have been shown to generate two orders of magnitude more muons per proton than the current Mu2e production target and solenoid. In contrast to the current Mu2e, the muon collider design has forward-production of muons from the target.

Slides WEYD6 [1.937 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEYD6

About •

Received ※ 06 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 09 October 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)